Advances in Raman optical activity (ROA) instrumentation based on the employment of a backscattering geometry together with a cooled backthinned CCD detector, a holographic notch filter, and a high-efficiency single-grating spectrograph have now enhanced the sensitivity to the level necessary to provide vibrational ROA spectra of most biological molecules in aqueous solution. Results on peptides and proteins show features originating in coupled C_(alpha )-H and N-H deformations of the peptide backbone which appear to be sensitive to the secondary conformation including loop and turn structures. Also carbohydrates show many features characteristic of the central aspects of carbohydrate architecture, with effects from the glycosidic link in oligosaccharides particularly prominent. Preliminary ROA spectra of pyrimidine nucleosides appear to reflect the mutual orientation of the sugar and base rings and the dominant furanose conformations.

Systematic measurements of optically induced birefringence in some optical active solutions are reported. Relative Kerr constants `B<sub>r</sub>' (relative to solvent), refractive indices n<sub>a</sub> (at (lambda) equals 488.0 nm) and n<sub>i</sub> (at (lambda) equals 694.3 nm), and densities `d' of the solutions under study were measured at room temperature in a wide range of concentrations. The absolute and molar Kerr constants `B<sub>o</sub>' and `B_m' were calculated as a function of the volume fraction. From these data, the microscopic parameters of the samples such as the specific Kerr constant, mean polarizability, anisotropic factors, optical polarizability, orientation function, orientation parameters, and effective induced dipole moment were calculated.

The first systematic measurements of the temperature dependence of optically induced birefringence in double-distilled water and optically active solutions in the temperature interval from 275 K to 328 K are reported. Also, the absolute value of the optical Kerr constant for water at room temperature (293 K) is measured. We found good agreement between earlier work and ours. The refractive indices and densities of the solutions also were measured in the same temperature interval. From our measurements, the nonlinear molar optical Kerr constant, orientational-redistributional molar optical Kerr constant, mean third-order polarizability and mean nonlinear polarizability for water, and optically active medium also have been determined.

Molecular left-right asymmetry is an origin of nonvanishing even order optical nonlinear susceptibilities of non-racemic solutions of chiral molecules. New non-linear optical spectroscopic schemes based on three- and five-wave interactions in chiral homogeneous isotropic media (symmetry forbidden in centrosymmetric racemic solutions) are investigated with the aim to develop a novel technique to clearly distinguish between left and right mirror isomers of biological molecules and to measure their individual nonlinear optical hyperpolarizabilities, and vibrational spectra. Through second harmonic generation (SHG) due to quadratic dipolar nonlinearity is still symmetry forbidden in optically active liquids yet we have succeeded in experimental observation, for the first time, of noncollinear SHG due to five-mixing process according to a scheme 2(omega) equals 3(omega) - (omega) , governed by a fourth order susceptibility tensor (chi) ⁽⁴D). SHG signal is found to be well collimated and quasi phase-matched, it shows theoretically predicted polarization, spectral and temporal properties.

The polarization-sensitive CARS methods were used for the resolving of overlapping bands of conformationally inhomogeneous molecules. The combination of this method with phase mismatching technique was used for an increasing of the sensitivity of PCARS method in a resolution of close lines. The experimental results of investigation of some organic molecules are presented.

Recent advances in optical technology have led to the development, at Glasgow, Scotland of a backscattering incident circular polarization (ICP) Raman optical activity (ROA) instrument. The higher S/N ratio and the greater control of polarization artifacts has allowed the study of protein samples to become almost routine. The advantage of ROA, over conventional Raman, is the far more prominent stereochemical sensitivity. In the case of the Glasgow instrument ROA is achieved by measuring the small difference between the Raman intensities in incident circularly right polarized and circularly left polarized light. We hope to utilize this chiroptical extension of conventional Raman to gain new insights into protein conformation and dynamics.

The structure of the tetrameric building block of vimentin intermediate filaments is determined by transient electric birefringence measurements. The decay time of birefringence, which is determined by hydrodynamic properties of the molecules, was found to be 4.4 +/- 0.5 microsecond(s) at 20 degree(s)C. This corresponds to a 62 - 67 nm long particle, assuming rigid rod- like proteins. This is in agreement with a staggered conformation of two approximately 45 nm long vimentin dimers. An in-register association of two dimers, resulting in an approximately 45 nm long tetramer, is not found.

Site-selective fluorescence spectroscopy and hole-burning spectroscopy have been performed for Zn-substituted myoglobin (ZnMb) in the red spectral region at low temperatures. The site- energy distribution of the chromophore and the fluorescence spectrum of ZnMb in a single site have been obtained from the analysis of laser-induced fluorescence spectra. It has been found that this single-site fluorescence spectrum can be regarded as the homogeneous spectrum. The comparison of the hole spectra between freeze-dried ZnMb powder and ZnMb in glycerol- water mixture shows that the phonon-sideband profiles of these spectra as well as that of the single-site fluorescence spectrum reflect the density of states of vibrational modes of the protein itself. The density of states of low-frequency vibrational modes of ZnMb weighted by the coupling strength between the electrons of the chromophore and the vibrations of the polypeptide chain has been determined from the above-obtained single-site fluorescence spectrum by solving an integral equation numerically.

Computer simulations of lateral diffusion of molecules in a biomembrane with obstacles were used to obtain the dependences of the diffusion coefficients detected by fluorescence recovery methods on the concentration of obstacles and for the calculations of transition probability densities (Green's functions) at various concentrations of obstacles. We show that fluorescence recovery curves can be calculated from the Green's functions.

Polarization sensitive coherent Raman spectroscopy (PCARS/PCSRS) was applied to study proteins in solutions in both two and three color configurations. In off-electron resonant PCARS the main problem is the nonresonant background, arising from the solvent. The advantage of PCARS is the resolving power as is demonstrated in the amide-I region of some proteins. Three color PCSRS was used to measure independently the (chi) ⁽³) components of hemoglobin resonantly excited in the (alpha) and (beta) absorption bands. From a simultaneous fit on different PCSRS spectra vibrational parameters were determined including phases and depolarization ratios. Besides the polarization and phase characterization of hemoglobin bands, we decomposed the vibrational amplitudes and phases into electronic contributions. Together with amplitudes, the phases contain information on electronic enhancement, vibronic coupling and symmetry of the molecular vibrations.

Surface second harmonic generation (SHG) has recently emerged as a promising new technique capable of probing the molecular organization at liquid interfaces. It provides information on the number of molecules adsorbed, the orientation and local environment of specific residues, and confers the ability to assess the symmetry of the intermolecular arrangement. Previously, SHG had been applied in the study of simple model systems where the major signal contributions originated from dye chromophores. Here we show SHG to be sensitive to submonolayer densities of the aromatic amino acids tryptophan, tyrosine, and phenylalanine adsorbed to the air/water interface, with the strongest resonant enhancement at the second harmonic wavelength of 266 nm being found for tryptophan. This observation opens the door for probing the ordering of peptides at liquid interfaces by exploiting the nonlinear optical properties of the tryptophan residues.

Two new optical methods for measuring size and velocity of quasi-spherical biological particles are proposed. One is an optical correlation method, based on the transformation of the transverse coherence function of the scattered field which forms the scattering particle images. A device for measuring the scattering particles size distribution function is proposed which has a response time of about 10 seconds, and can be applied to measure particles having sizes in the range of 3 to 500 micrometers to within 10%. The other is a holographic continuous exposure method for studying the dynamical and structure characteristics of the Brownian motion of unicellular algae. The measured algae velocity and size distribution functions are reported.

The effect of lecithin concentration on the refractive index behavior in a perturbed water- lecithin system is investigated using a polarization interferometer. It is found that the time variations of the refractive index for different lecithin concentrations can be used to assess the state of the lecithin in water, i.e., detect micelles, single and double molecular layers, etc.

Fluorescence and Raman spectroscopic analysis has been developed at the subcellular level, using laser excitation under the microscope. This approach has been successfully used on single living cells to monitor different biological molecular processes. The experimental applications which are presented here give an illustration of the performance of the method to obtain kinetic, topographic (spectral imaging), or quantitative data.

We present information about a scanning-FRAP apparatus built in our laboratory and current research activities concerning biomembrane dynamics.

We present here the study of intracellular distribution of doxorubicin in the single living cell by scanning confocal fluorescence microscopy, with argon laser excitation and photon counting detection. New results on the nuclear and cytoplasmic drug fluorescence not detectable by conventional microscopy are discussed. Differences in the fluorescence pattern observed in living and fixed cells suggest new insights in the mode of action of the drug.

Both for medical and biotechnological purposes it is very important to be able to analyze and manipulate cellular populations on a single cell basis. Moreover it is often important to be able to sort a subfraction of cells from the total population with defined specific characteristics. Since the retainment of biological viability is of importance in such cases the use of monoclonal antibodies for cell characterization cannot always be applied. The use of light scattering offers an attractive alternative. One of the manipulations which is at the beginning of many biotechnological processes is the fusion between two well characterized and differing cell types. In the present paper we concentrate on the use of flowcytometry for light scattering characterization and fusion of cells.

The viscous properties of blood are of major importance for circulation in vessels with diameters less than 100 mm. The disturbance of microcirculation is observed in many pathologies. The blood viscosity under low shear rates is determined by the aggregation ability of erythrocytes. So, an important problem of hemorheology is the determination of the durability of aggregates, their sizes, and the aggregation kinetics. To measure these parameters the nephelometric technique is widely applied in different modifications enabling the registration of the backscattered or the transmitted light intensity. We present here the results of our study of peculiarities of the (dis)aggregation kinetics in relation to different pathologies: psoriatic arthritis, inherited hypercholesteremia, inherited homoglobinopathy, and some others. These results show the high diagnostic potentials of laser nephelometric technique.

The potentials and first results of a combined Raman microspectroscopic and atomic force microscopic study of the banding pattern of polytene chromosomes are described. The results of Raman experiments indicate that differences in DNA content between bands and interbands are not as large as previously suggested in the literature. By means of atomic force microscopy the ultrastructure of chromosome bands and interbands can be analyzed.

The influence of Nd/YAG laser irradiation (532 nm) on the MC-540 stained POPC and DMPC liposomes (lipid:dye ratio 42:1 - 20:1) was studied by absorption spectroscopy in the range of 380 - 700 nm. Two absorption bands (533 nm and 567 nm) corresponding to two colored species of the dye -- monomers and dimers -- were observed for MC-540 in phospholipid liposomes. MC-40 monomer-dimer distribution was shown to depend on the liposome composition and lipid:dye ratio. Irradiation of the samples by laser light of fluence rate 3000 W/m² resulted only in MC-540 monomer-dimer distribution changes. The variation of this effect was observed as the kind of liposomes (alcoholic or ultrasonic) were changed. MC-540 monomer-dimer distribution is one of the factors that affect the dye- mediated photoinactivation. Illumination by intensive laser light (60,000 W/m²) caused color fading of the MC-540 dye.

The effect of KCl ions on hematoporphyrin (HP) and its binding to DOPC liposomes were investigated. The absorption spectra of HP (2 - 30 micrometers ol/l) in KCl solutions (0.1 - 1.0 mol/l) showed two intensive peaks at 390 nm (monomer peak) and at 374 nm (dimer peak). When these samples were kept in the dark an agreement with HP aqueous spectra was observed. He-Ne laser (632 nm, 1 mW) illumination of the dye in KCl solution resulted in a change of the spectral appearance: both the original absorption bands became less distinguishable up to their disappearing and a new band at 404 nm was found. Its intensity was systematically enhanced as the time of illumination was increased (5 - 40 min.). This effect can be attributed to the laser energy mediated interaction of HP with ions.

The paper deals with recent data of investigations and medical adaptations of waveguide cw and TEA carbon dioxide lasers with flexible fibers. The silver halide polycrystalline fibers with lengths up to 1.8 m and diameters 0.5 - 2.0 mm are used. The main attention is given to transmission of high power radiation and reducing of output beam divergence. Power at the fiber end is up to 43 W in the case of cw laser and 100 kW (pulse duration approximately 100 ns) with TEA laser. For work of long duration it is necessary to halve the power. The magnitude of output radiation divergence equal to 6 degrees (full angle) for uncladded fiber with 1 mm diameter has been achieved.

Vibrational Raman spectroscopy has proven to be a powerful tool for biomedical applications such as the molecular characterization of normal and pathological tissues as well as the evaluation of prosthetic material bicompatibility. This work deals with the applications of Raman spectroscopy to the study of ocular tissues (lens, cornea, vitreous humour), the respective prosthetic biomaterials, bone tissue, and the main biomaterials used in the prosthetic surgery of bone. In particular the Raman spectra of the cornea in different conditions, of vitreous humour, and of pathological bone are reported and discussed. The Raman spectrum of air dried cornea suggests that the tissue is made up almost entirely of collagen. The spectra of normal and pathological bone tissues indicate that pathological bone has a more minor phosphate content than normal bone and some modifications are also observed for the amide III components. Moreover, the Raman spectrum of an arthroplastic bone before defatting suggests a substitution of phosphate with carbonate ions.

The laser spectroscopy methods are proposed for organic constituents of the expired lung air detection for diagnosis of diseases. The results of acetone concentration measurements are presented.

Raman, FTIR, fluorescence, and UV-visible spectra are used to study interactions between amuloid-labelling dyes and poly-L-lysine and bovine insulin, two proteins which play the role of models of (beta) amyloid of Alzheimers disease. It is found that though the (beta) conformation of the peptide is not essential, it helps to encourage binding which appears to be stable and specific in nature, involving SO₃- groups of the dyes and NH₂ groups of the proteins.

The photoinduced damage sensitized by chlorin e₆ to obligate-pathogenic bacteria Klebsiella rhinoscleromatis in the presence of streptomycin has been studied. A significant synergic effect is observed resulting in both higher photoinactivation rates in the presence of streptomycin and reduction of the threshold of toxic antibiotic concentrations for bacteria, exposed to the sublethal photosensitized action. One may expect that the use of the combined action of a photosensitizer and visible light will allow one to decrease an effective antibiotic dose using combined photo- and chemotherapy of scleroma.

It was shown that exposure of the AZT derivative 5'-(1,4-dihydro-1-methyl-3- pyridinyl-carbonyl)-3'-azido-2', 3'-dideoxythymidine) (H₂PyrAZT) in aqueous solution to pulsed laser emission ((lambda) equals 355 nm, pulse length 2 ns) gives rise to photoelectron ejection by stepwise two-photon absorption. Absorption spectra of the semioxidized radicals obtained in this reaction were determined. It was shown that the photolysis did not affect the azido group.

Methods for preparation of chlorin sensitizers for PDT of cancer on the base of purple bacteria and blue-green algae have been elaborated. New bacteriochlorophyll a derivatives have been synthesized. Bacteriopurpurin and bacteriochlorin p₆ have strong absorption at 818 and 770 nm respectively.

The time-dependent fluorescence Stokes shift and kinetics of emission anisotropy of the 1- phenilnaphthylamine (1-AN) probe in solutions and phospholipid bilayer membranes have been examined using subnanosecond laser fluorimeter. It is shown that the electronic spectra of probe in polar viscous and rigid solutions and in vesicles are inhomogeneously broadened. The obtained results prove the existence of the earlier unknown effect of the wavelength- dependent rotation of a probe in bilayer membranes. This rotation exceeds the equilibrium Brownian one and occurs due to the realization of intermolecular interactions energy excess during the relaxation. The free-energy diagram is presented which makes it possible to interpret the whole set of experimental data. A new method for determination of a probe localization and dielectric constant distribution along the polar region of bilayer membranes is suggested. It is found that the function of the probe molecules distribution along the polar region of membranes is well described by Gaussian.

Laser-Doppler velocimetry (LDV) is an established technique for noninvasive monitoring of skin blood flow. The LDV is based on the interference between the photons scattered from the moving red cells and the surrounding stationary tissue. In this work we have developed a new chopper stabilized LDV method. The light bema from the 10 mW HeNe laser was pulsed by a mechanical chopper at a frequency of 130 Hz. The light pulses backscattered from the skin were measured by a dual PIN photodiode electrometer amplifier. In the Fourier spectrum the chopper 130 Hz + harmonics peaks were dominating. The width of the peaks was diminished when measuring necrotic skin areas. The interference signal was demodulated by multiplying the measured pulsed signal by the chopper waveform. The resulting LDV spectra had a negligible amount of electrical distortion. The main advantage of the chopper stabilization is that pulse modulation concentrates the signal power near the chopper frequencies, which are free of electrical 50 Hz + harmonics pick-up.

The comparative studies of SLR effects vs chemical adaptogens effects on animals poisoned by industrial poisons and SLR as compared to traditional radio-protectors effects on gamma- irradiated animals were carried out. Obtained results show the stressed adaptogenous effect of SLR.

Experiments on the determination of the possibilities of laser fluorescent spectroscopy for detecting the distribution and time of presence of methoxypsoralens (chemical substances of furocoumarin class) in human epidermis have been carried out.

The irradiation of an aqueous solution of the hematoporphyrin causes the formation of the stable photoproduct that may play an important role in the cancer therapy. The spectral and kinetic characteristics of the absorption changes of hematoporphyrins and their photoproducts were measured by picosecond pump and probe absorption spectrophotometer with continuous tunability of pump and probe pulses in the spectral region of 400 - 1500 nm with an accuracy better than 10^-3 optical units and with the temporal resolution less than 10 ps. The careful examination of the absorption difference spectra showed that the photoproduct is involved in aggregates or exists as a part of the covalently linked oligomer of hematoporphyrins. In addition, an in vitro investigation has been carried out in the solutions and cells to evaluate the influence of preillumination of porphyrins on the efficiency of damaging the cell's membrane integrity after irradiation by red light.

Photodynamic therapy (PDT) of malignant tumors is based on the property of some photosensitizers to be accumulated by tumour tissues'. On subsequent illumination with light of the wavelength absorbed by these photosensitizers tumour cells can be destroyed. Hematoporphyrin derivative and similar agents presently have some negative features. First, these agents do not possess optimal absorption spectrum. In particular the absorbance in the red region is not very high. Second, the composition of these agents varies for different preparations and with the storage time. Third, they do not possess a sufficient selectivity for malignant cells. Furthermore, they are also accumulated in skin causing its damage upon exposure to light. Thus at present the developing of the effective PDT photosensitizers is of great interest. Recently some of this interest has been focussed on the phthalocyanines (PC). These dyes have sufficient molar extinction coefficient (<10 M1cm1) in red region of optical spectrum (650 700 nm). They are non-toxic. Some of them are effective photosensitizers and produce singlet oxygen. They are relatively easy synthesized and resistant to chemical degradation. PC can have different groups added to the external macrocycle perifery. These groups mainly determine chemical properties and solubility. They offer possibility to bind the dyes to any other molecules, for example, proteins. The properties of naphthalocyanines (NC) are rather similar to the ones of PC, but the most efficient absorption band is in region of 750 - 800 nm. An important problem is to increase the ratio between the level of photosensitizer in malignant and normal tissues. One of the possible solutions is the use of photoimmunotoxins, i.e. conjugates of photosensitizers with monoclonal antibodies (mAb) against cancer antigens or tumor marker. Experiments with immunoglobulin-hematoporphyrin2 and dimetoxyhematoporphyrin3 as well as chiorin e6 conjugates4 showed that they retained both photochemical properties of free dyes and immunological ones of antibodies.

Certain properties of the YLF-Er laser, operating in the 3 micrometers wavelength range, were investigated. The influence of the 3 (mu) free-running YLF-Er laser radiation on a rabbit's cornea was studied.

In this work, the study of the lamp pumped YLF-Er laser operated at four spectral ranges around 0.85, 1.23, 1.73, and 2.84 (mu) under comparable conditions are presented to clarify the possibilities of creation of multi-wavelength lasers, in which erbium doped yttrium-lithium double fluoride crystals (LiYF₄-Er or YLF-Er) have been used as lasing media. Characterization of the YLF-Er multi-wavelength lasers are given, and the thermo-optic studies and second harmonic generation (0.425 (mu) ) of 0.85 (mu) YLF-Er laser emission have been performed. The laser properties of the three types of YLF-Er lasers from a series of new laser systems are presented: the single-wavelength 2.84 (mu) YLF-Er laser, the two- wavelengths <<blue>> YLF-Er laser operating at 0.425 and 0.85 (mu) , and the multi-wavelength YLF-Er laser generating at 0.85, 1.23, and 1.73 (mu) . The laser action of different wavelengths on the biological tissues are discussed.

Methods of theoretical description and experimental investigations of the optical characteristics of biotissues are presented. Propagation of focused and collimated laser beams in multilayer biotissues is described. Using the speckle-optics techniques pulse wave monitoring was realized. Techniques and devices for laser therapy with respect to laser light dosimetry in treatment of different diseases are presented.

In this paper diffraction of focused laser beams in thin blood vessels is discussed. A theoretical description of this process is given, a number of model experiments are carried out. Relations establishing the dependence of the scattered field parameters on the characteristics of blood flow in vessels, the diameter of which is about erythrocytes size, are obtained. The relations between the optical signal characteristics and the position of the observation point of speckle- field is discussed. The investigations of the dependence of the space-time projection structure of the speckle-interferometer output signal on heart disease seriousness have been carried out. The novel technique of heart disease diagnostic is suggested. The results of experimental investigations of pulse waves, using the differential speckle-interferometer, are present. The traditional speckle-interferometer Michelson type and differential speckle-interferometer for cardiovibration measurements are compared. Difficulties, appearing from use of the suggested diagnostic method, are analyzed and ways of their elimination are found.

A theoretical aspect of frequency domain measurements of tissue optical parameters is considered. In the framework of radiative transfer theory expressions have been obtained which describe dependence of modulation M and phase shift (Delta) (Phi) of scattered radiation on frequency. As an example, the results of processing of experimental data are presented.

The brief review of experimental results on the light scattering (both linear and nonlinear) in liquid crystals in critical range, which have been obtained by the original homodyne technique, is presented. The multiplicative nature of the molecular fluctuations in the medium under external field and physical consequences of that are discussed.

We have employed dynamic laser light scattering to investigate the solution behavior of RecA protein from Escherichia coli. RecA is essential for genetic recombination, in vivo, and is the central catalytic protein component of the analogous strand exchange reaction that occurs in vitro between strands of duplex DNA and a homologous single strand. In solution RecA exists in a variety of aggregated forms with sizes and distributions that strongly depend on magnesium concentration, pH, and temperature. With increases in [MgCl₂], temperature or addition of sub-stoichiometric amounts of short duplex DNAs, larger aggregates of RecA are formed. In contrast, increasing pH from 7.3 to 9.0 results in formation of protein aggregates with overall smaller dimensions. Our measurements have also revealed the initial aggregation state of RecA and MgCl₂ induced aggregation depends on the protein preparation procedure. If extreme care is not taken a significant amount of very large, irreversible aggregates contaminate the preparation. These protein species do not display appreciable amounts of magnesium or temperature induced aggregation.

The effect of the insertion of different amounts (from 0 to 6) of the curved sequence AluI in pUC18m plasmid (2686 base pairs, bp) is studied by dynamic light scattering. This sequence is a highly repeated 113 base pairs long sequence from Artemia Franciscana shrimp. A 30% compaction of the plasmids containing 2 and 6 adjacent AluI sequences compared to pUC8 plasmid (2717 bp) is observed. Furthermore the behavior of the translational diffusion coefficient D_t versus the number of adjacent AluI insertion is not monotonic.

As a final stage of cell signal transduction, secretory cells release hormones by exocytosis. Before secretory granules contact with the cell membrane for fusion, an actin network barrier must dissociate as a prelude. In order to elucidate dynamical behaviors of secretory granules in actin network, in vitro assembly and disassembly processes of actin networks were examined by means of dynamic light-scattering spectroscopy. We studied actin polymerization in the presence of chromaffin granules isolated from bovine adrenal medullae, and found that the entanglement of actin filaments rapidly formed cages which confined granules in them. We also studied the effect of gelsolin, one of the actin-severing proteins, on the network of actin filaments performed in the presence of chromaffin granules. It turned out that the cages which confined granules rapidly disappeared when gelsolin was added in the presence of free Ca²⁺ ions. Semiquantitative analyses of dynamic light-scattering spectra permitted us to estimate the changes in the mobility (or translational diffusion coefficient) of chromaffin granules in the actin network with its assembly and Ca²⁺-dependent disassembly by gelsolin. Based on the present results and some pieces of evidence in literature, a model is proposed for biophysical situations before, during, and after an exocytotic event.

Light scattered from all gel systems is non-ergodic, i.e., only partial spectral broadening occurs and the scattered speckle pattern has a stationary component. Autocorrelation functions in general have both homodyne and heterodyne components, but recent theoretical work has cast doubt on the interpretation of such data when the coherence factor of the optical system, (beta) , is other than unity. An empirical investigation has therefore been made using a well defined system, in which the degree of spectral broadening is already known. It has been shown that the method previously described in which the correlator is run while scanning angles of scatter, is valid irrespective of the value of (beta) . The extent to which (beta) influences the interpretation of the results in any one arbitrary position is discussed.

By combining fluorescence recovery after photobleaching with gel electrophoresis, known as movements of fluorescence pattern after photobleaching (MOFPAP), it is possible to measure the time-dependent electrophoretic mobility of stained DNA fragments in a gel over relatively short time periods. The creation of a narrower stained DNA band by photobleaching can also shorten the running time and increase the resolution in a gel electrophoresis experiment for analytical purposes. In addition, a frequency analysis of MOFPAP signals has been simulated to demonstrate the potential capability of MOFPAP as an analytical tool for determining the presence of multiple species of DNA fragments in gel electrophoresis by measuring the electrophoretic mobility of each species present without spatial separation of different DNA fragments.

The fluorescence polarization anisotropies of ethidium intercalated in duplex DNAs containing 12 to 60 bp were measured and analyzed using a theory of deformable rods to obtain their hydrodynamic radii (R_H). The apparent R_H is 10.0 +/- 0.2 angstroms for 12 and 24 bp, but increases to 11.5 - 12.0 angstroms between 40 and 60 bp. This variation in R_H is attributed to the presence of slowly relaxing bends in the DNA. Consequently, the static equilibrium persistence length must be much smaller than the dynamic persistence length (P_d) defined by the dynamic (instantaneous) bending rigidity. We estimate that P_d > 1000 angstroms. R_H of a 48 bp duplex DNA is largely independent of NaCl concentration, which suggests that interionic forces do not much affect the rotational friction. However, R_H depends significantly on the concentrations of other ions, especially Mg²⁺ and Mn²⁺, which are believed to affect the hydration of DNA.

A quantitative study of the rise, magnitude, and decay of birefringence of DNA in agarose gel under an electric pulse E has been performed. It provides us with the molecular weight dependence of the characteristic times which describe the deformation of the chain during the transport and which are the parameters requested for designing electric pulse programs for pulsed field gel electrophoresis capable of achieving separation of DNA fragments of very high molecular weight.

Vegetable marrows (cv. Seme Bolognese) and peach fruits (cv. Suncrest) were stored at different chilling temperatures in order to evaluate, by vibrational spectroscopy, the unsaturation degree of the total lipidic component and other possible markers of chilling injuries. Capillary Gas Chromatography also has been applied to evaluate the unsaturation degree of the esterified fatty acids. Both methodologies indicate a general increase of the unsaturation degrees with storage time. This can be interpreted as a better adaptation capability of the fruits to low temperatures. Moreover, the FTIR-ATR methodology points out the onset of a hydrolysis reaction of the esteric phosphate group of phospholipids during storage.

The paper is devoted to results of lidar technique application for ecological investigation in the Russian coastal zone of the Black Sea in August of 1991. The shipboard lidar system for remote sensing of phytoplankton and organic admixtures (dissolved organic matter and oil- products) is described. The features of horizontal distributions of chlorophyll-a and organic matter in local and mesoscales are discussed. The relationship between these features and anthropogenic (industrial activity, pollutions) and natural influences (rivers, etc.) are analyzed.

The potential role of lidar technique in the system of biomonitoring of the sea and difficulties of data interpretation are discussed in the paper. Recent development of lidar implementation of pump-and-probe technique may be considered as a step toward solution of some related problems. This novel lidar technique may be classified as `super-active.' The pump-and-probe shipboard lidar system is described in the paper. The results of field tests and applications (the North-Western Atlantic, 1990; the Mediterranean Sea, 1991) of the developed technique in biological oceanography are discussed. The horizontal distributions of phytoplankton photosynthetic activity and chlorophyll fluorescence in synoptic and meso-scales, as well as correlation with hydrological structures and diurnal variations of measured characteristics, were studied. The problems of future development are discussed.

The results of simultaneous lidar monitoring of phytoplankton (PP) and organic matter (OM) horizontal distributions in the subsurface layer of the Baltic Sea are presented in the paper. A special shipboard lidar system has been developed. Total length of the monitoring route was 8390 km. The horizontal distributions of near-surface PP and OM for the second half of May and the first ten days of June were reconstructed using the data obtained. The polluted areas near the industrially active regions were detected. Diurnal rhythms of PP fluorescence were measured in situ by lidar. It proved the necessity of adjustment of lidar data for such diurnal variations. The temporal divergence of detected structures was explored. For most parts of the area, averaged time of divergence for phytoplankton horizontal distribution was estimated as 1.2% per day.

A totally computerized multi-function laser gas analyzer operating within 3 micrometers spectral region is described. The application of this device for IR absorption high resolution spectroscopy, for environmental control (long-path gas analysis), and for diseases diagnosis is discussed.

A description of the general principles being developed at Moscow University for laser diagnostic methods of monitoring water ecosystems is presented in the present paper. A brief historical survey of investigations in this field is provided with the formulation of the problems which should be solved. The latest results obtained in Moscow University are summarized. These results are discussed in a series of papers presented in these proceedings and reported at several recent international conferences.

Mechanisms of solar illumination influence on phytoplankton chlorophyll-a fluorescence and photosynthetic activity were investigated in situ by means of lidar implementation of the pump-and-probe technique. It has been found that for subsurface phytoplankton the main mechanisms of sunlight regulation were photoinhibition of primary photosynthesis processes by excessive light, dominating at illuminations more than 40 klx, and `energy-dependent' fluorescence quenching, at illuminations 5 - 20 klx. The potential role of other regulating mechanisms (photophosphorylation of pigment-protein complexes, spillover, xanthophyll cycle, lipids, and pigments photodestruction) are discussed and analyzed.

The main factors which determine the nature and mechanism of penetrating of organic compounds into the water ecosystems of southern Belarus are discussed. Composition and content of pollutant compounds of organic and mineral nature are presented for the number of ecosystems in Belarus. The results of investigation of organic compounds in natural water resources using subnanosecond laser spectrofluorimeter are presented.

The mathematical self-modeling method has been used to identify the samples of urban air from their IR spectra. The spectra of methane, carbon dioxide, carbon oxide, acetylene, and ethylene have been isolated from the spectra of samples. The data obtained have enabled us to investigate the ethylene content in the ambient atmosphere as a function of daytime using laser optoacoustic analysis.

Aiming to an early detection of forest decline, prompt and delayed luminescence of spruce needles was studied from the picosecond to the second time range using novel laser diodes and highly sensitive detection systems. In particular, (1) subnanosecond fluorescence decay measurements showed a superposition of at least three exponentially decaying components, the largest of which (decay time (tau) equals 2.0 - 3.5 ns) represented some `dead' chlorophyll or closed reaction centers. This component is more pronounced in slightly damaged than in healthy spruces and can be used to monitor the early steps of photosynthesis. (2) Delayed luminescence -- which is supposed to report on the electron transport chain as a whole -- could also be correlated with the physiological state of the individual spruce. In general, healthy and declined spruces showed the highest photosynthetic efficiencies during the summer period, but also the most pronounced stress symptoms -- probably due to high irradiance, drought, and increased ozone concentrations.

The phenomenon of pulse alteration of bioelectric potential difference (BEPD) U_(Beta ) approximately 10 mV between the top and the base of a plant is observed when a leaf is irradiated locally by a low intensity laser beam ((lambda) equals 632.8 nm, W approximately 40 mW/cm²). This effect is absent completely if an infrared laser ((lambda) equals 828.3 nm, W approximately 40 mW/cm²) is used for irradiation. There exists a threshold value of the background illumination below which U_(Beta ) equals 0. The speed of U_(Beta ) propagation from the irradiated zone along the axes plant organs is around 8 mm/sec. We observed the effect of U_(Beta ) transmission from the irradiated two weeks plant cucumber to a nonirradiated one, if the plant roots are contacting in the soil. We observed also the complex periodic BEPD response to the periodic local laser irradiation.

Studying mountain geosystems by remote sensing, both by the spectral-zonal space-borne images and by laser-induced fluorescence, is presented. Space images help to quickly obtain a full picture of the pattern of pollution which is hard to achieve through ground investigations; but concrete detailed information about the object under study may be obtained by helicopter- boarded laser-spectrometer for fluorescent analysis.